In the installation of airport runway touchdown zone, centerline and edge lighting systems, as well as in the installation of taxiway centerline and edge lighting systems, and other lighting systems, certain steel containers are utilized. These containers are embedded in the runway, taxiway and other pavements at the time these runway and taxiway pavements are poured.
These containers, hereinafter referred to as embedded containers, vary in length and diameter and provide an inverted flange at their top portion, which has a standard set of threaded holes to allow for the runway, taxiway, edge and other light fixtures to be bolted onto them above the pavement surface. These light fixtures, otherwise known as airport inset lights, have to be aligned with respect to each other in a perfectly straight line, in the horizontal plane.
These embedded containers below the pavement surface serve as light fixture bases. They also serve as transformer housings and junction boxes. Depending on the location where these containers are installed they are exposed to varying degrees and types of forces applied to them by the aircraft and other vehicular traffic in that location. For example, runway and taxiway centerline light fixtures and the containers they are bolted onto are subjected to direct aircraft and other heavy vehicular loading applied to the top flange of the container and transmitted down to its walls.
When a runway, taxiway and other aircraft traffic area are first built, or when upgrading, modernization or maintenance projects require their re-surfacing (repavement), the flanges on the embedded containers get buried under the pavement. This creates the need for height adjusting devices with flanges identical to those of the embedded containers, in order to adapt said container up to the final surface and for the lighting fixtures to be installed and aligned above the pavement. In many instances this requires core-drilling the newly poured pavement in order to reach down to the now buried top flange of the embedded container.
Depending on the lengths of the runways and taxiways, thousands of these embedded containers are affected and a wide variety of height adjustments is involved for each given size of embedded containers.
At present fixed-length extensions, which have to be made in many different lengths, are utilized to provide the many different gross height adjustments. A combination of one or more flat spacer rings, which are manufactured in thicknesses of 1/16, 1/8, 1/4 and 1/2 of one inch and others, is used to provide the final height.
These fixed-length extensions have one inverted flange on each end in order to bolt it onto Embedded Container 3, then flat rings are added on top of the fixed-length extension top flange before the lighting fixture is bolted on to said flange.
The fixed-length extensions and the spacer rings, both the tubular types as well as the flat types, have to be individually ordered to meet the required length. This means:
1) Field measurements of each individual fixed extension length is required for every container.
2) Record keeping of those measurements for ordering and verification.
3) Ordering, receiving and delivering each size to its location, and to the field.
4) Frequently having to install more than one fixed-length extension and more than one flat ring in order to achieve the required height.
The complications in the installation listed above are further magnified by the fact that the embedded containers are made in 4 different sizes: 10, 12, 15 and 16 inches in diameter.
One additional aspect of the installation of the light fixtures upon the embedded containers is their alignment with respect to one another in a perfectly straight line, known as azimuth correction or alignment.
It is therefore a principal object of the invention to provide a method and means for adjusting with precision the height of embedded containers and for aligning, with great simplicity and precision, the light fixture that is installed upon it. The means by which the precise height adjustments and the precise azimuth corrections will be made is herein generally described as the adjustment assembly.
A further object of the invention is to provide a method and means for adjusting the height of embedded containers without having to install individual fixed length extensions and flat rings.
These and other objects of this invention will be apparent to those skilled in the art.